Keep a seat for an unnamed plus-one

Count the plus-one as a person who needs a seat, even before you know their name. Do not treat the empty name as zero, and do not add a ninth chair to an eight-seat table to make room.

A placeholder that already has a seat

Alex's unnamed guest holds a seat at Alex's table
Table	Capacity	Guests
A	8	Alex, Alex's guest, A1, A2, A3, A4, A5, A6

Synthetic. The placeholder is a seat, not zero. Naming them later changes the label, not the table, in this example.

When the name arrives

In this example, replacing "Alex's guest" with a name does not move anyone. The party and the table stay. If the named guest cannot sit at that table, that is a new constraint, not a rename.

A named child is a different party again: seating children covers when they sit with parents and when they do not. If the list arrives with unnamed plus-ones, the import walkthrough shows how they survive the file.

How many plus-ones to plan for

Plus-ones account for 9 percent of the coded seating problems in our forum corpus. The share is small; the failure mode is not. An unheld plus-one turns into a table move three days before the wedding, and the move is what people remember.

Hold the seat, then count it. At an eight-seat round, one held seat per table across ten tables is ten spare seats — one table's worth. If your invitation rate suggests more plus-ones than that, add a table rather than squeezing a ninth chair in; an eight-seat round at 12 ft centres does not take nine without losing the walkway.

The hold-seat arithmetic

You cannot know the final list early, and you should not try. What you can do is decide how many seats to hold, and where. A spare seat at a table costs nothing if the table is already placed; a spare table costs a cloth, a centrepiece and floor.

At eight-seat rounds across ten tables you have eighty seats and eighty-one possible guests before the list moves. One held seat per table gives ten spare chairs, and ten late yes answers land without touching a table. Holding a whole table gives eight, and it costs the room.

Named plus-ones, unnamed plus-ones, and the third kind

A named plus-one is a guest: you know the name, and they get a seat and a place setting. An unnamed plus-one is a reservation, and it needs a deadline — the RSVP date, not the week before — because a reservation that never resolves keeps a seat out of the chart for months.

The third kind is the guest who adds someone after the deadline. Plus-ones are 9 percent of the coded seating complaints in our forum corpus. Nearly all of those are this one, and it lands with the printed tables.

A plus-one after the deadline

Look for the table that already holds their partner or their friend, and check it has a spare chair. If it does, seat them and nothing else moves. If it does not, move one existing guest from that table to a table with a spare, and say so to that guest rather than to the room.

If neither exists, the honest options are a ninth chair at an eight-seat round — which costs the walkway — or a new table, which costs the floor. Pick one, write it down, and tell the venue the new number.

What to put on the invitation

Name the plus-one or do not offer one. "And guest" is an offer with no deadline, and the guests who take it late are the ones who make the chart move after the cards are printed. If you want the option without the churn, name the person you would invite.

If the budget cannot carry unknown plus-ones, say so plainly on the RSVP page and put the seat you can spare into a table that already exists. A stated limit reads as a plan; a silent one reads as a mistake when the extra guest arrives.